A magnesium alloy, which comprises magnesium and other additives such as aluminum, is lightweight and easy to work with, and is used in many fields of art. For example, AZ-series magnesium alloys, which contain Al, Mn and Zn, are high in yield strength and tensile strength, and are advantageously used where a high mechanical strength is required. AS-series magnesium alloys, which contain Al, Mn and Si, are known to have heat resistance besides the properties of the AZ-series magnesium alloys.
However, since the AS-series magnesium alloys are limited in heat resistance, magnesium alloys which further contain Ca have been developed to improve the high-temperature properties.
For example, the below-identified Patent document 1 discloses magnesium alloys containing 2-10% by weight of Al and 3.0-5.0% by weight of Ca such that the relation Ca/Al≥0.7 is met, and further containing additives selected from Zn, Mn, Zr, rare earth elements, and Si (paragraph 0017 of Patent document 1). By the actions of Si and rare earth elements, these magnesium alloys show improved heat resistance.
The below-identified Patent document 2 discloses a magnesium alloy containing 1.6-5.0% by mass of Sn, besides 3.0-9.0% by mass of Al, and 2.5-7.0% by mass of Ca, and explains that by the addition of Sn, this magnesium alloy shows improved creep properties (paragraph 0021 of Patent document 2).